Cutting fluids such as lubricants and coolants have long been employed for lubricating and cooling cutting inserts and workpieces and to aide in the ejection of chips. At first, devices for dispensing cutting fluids were mounted externally to the cutting tool itself. Such devices proved to be cumbersome and inhibited upward ejection of chips due to a downward flow of the cutting fluid onto the cutting region.
More recently, rotatable cutting tools have been provided with internal cutting fluid systems. These systems typically include a sleeve which is placed about a "circular section" of the tool body. The rounded circular section has a cross-bore for conveying the fluid from the sleeve to the inside of the tool body.
The sleeve containing the cross-bore is rotatably mounted over the circular section. The cross-bore in the sleeve is alignable with the cross-bore in the circular section to provide a passageway for the flow of the cutting fluid into the tool body which enters the sleeve from a stationary source. When the cross-bore of the circular section is contiguous with the cross-bore in the sleeve cutting fluid flows into the tool body and forward through an axial channel and out an ejection port in proximity to the cutting insert.
This design which is typical of existing internal cutting fluid systems has at least three significant disadvantages which render it of limited use in commercial machining operations. First, the flow of cutting fluid into the circular section is intermittent in that cutting fluid is able to flow into the tool body only when the respective cross-bores are aligned which occurs once for each revolution of the tool body. This results in a reduction of the potential pressure of the cutting fluid that exits the ejection port and thus is of limited value in aiding in the removal of chips formed at the junction of the cutting insert and workpiece.
The second disadvantage of the aforementioned system is that a crescent-shaped gap exists between the flat surface of the circular section and the contiguous round inner surface of the sleeve. This gap allows some cutting fluid to avoid passing into the central bore of the flange thereby reducing the pressure of the cutting fluid exiting at the cutting insert.
A third disadvantage is that the coolant collar must be mounted on a specified circular area to accommodate the width of the collar (e.g. 2") which increases the overall length of the tool. This is especially disadvantageous when length: diameter ratios are critical to performance.
It is therefore an object of the present invention to provide an internal cutting fluid system which enables a continuous flow of fluid from a stationary source to the cutting insert of a rotatable cutting tool.
It is another object of the invention to provide a collar which has a slender profile and has the same width as a thin flange to minimize the length to diameter ratio to improve the rigidity of the cutting tool.
It is a further object of the invention to provide a collar which can be mounted about a flange section of a rotatable cutting tool in which there is full and flat face to face contact between the flange section and the collar to thereby enable the continuous flow of fluid therethrough without loss of pressure.
It is still a further object of the invention to provide a rotatable cutting tool incorporating the collar of the invention to provide a cutting tool having an internal, continuous flow cutting fluid system.
It is another object of the invention to provide a cutting tool in which the flange is integral with the tool body to provide greater strength in the region of maximum stress.